(1) Field of the Invention
The present invention relates to a method for affixing an adhesive tape to a semiconductor wafer subjected to surface treatment in order to protect a surface of the semiconductor wafer, and an apparatus using this method.
(2) Description of the Related Art
JP-A 2004-025438 discloses one example of a technique for affixing an adhesive tape to a semiconductor wafer. According to this technique, an adhesive tape fed from a tape supplying section is affixed to a surface of a semiconductor wafer while being pressed against the surface of the semiconductor wafer by an affixation roller. In this technique, the adhesive tape is fed from the tape supplying section by a tensile force generated when the affixation roller moves relative to the semiconductor wafer while pressing the adhesive tape. Herein, a back tension is applied to the tape supplying section so as to prevent the adhesive tape from being fed excessively or to prevent the adhesive tape from sagging.
In a case of affixing an adhesive tape to a semiconductor wafer, a tensile force to be applied to the adhesive tape is unbalanced, so that the adhesive tape affixed to the semiconductor wafer becomes ununiform in thickness. Consequently, there arises a problem that the semiconductor wafer becomes ununiform in thickness in a subsequent back grinding process.
In addition, there is a possibility that the semiconductor wafer is warped or deformed due to shrinkage of the adhesive tape affixed to the semiconductor wafer while being applied with an ununiform tensile force, so that trouble is caused in the back grinding process.
In order to solve these problems, according to the technique disclosed in JP-A 2004-025438, a back tension applied upon affixation of an adhesive tape to a semiconductor wafer is temporarily made small; thus, the adhesive tape is affixed to the semiconductor wafer without being applied with an undue tensile force.
Such small back tension makes it possible to prevent the adhesive tape from being applied with an undue tensile force, but causes a problem that a wrinkle occurs at the adhesive tape.